The present invention relates generally to vehicle safety device actuation systems, and more particularly to a method and system for providing early and reliable vehicle roll-over detection.
Generally, typical vehicle roll-over detection systems utilize electro-mechanical sensors, such as mercury filled inclination sensors and/or gyroscopes, which are arranged to close a switch contact in response to the forces generated by a vehicle roll-over. Known systems have not proven wholly satisfactory because these sensors tend to rely on a mechanical action responsive to the vehicle rolling over which makes a high sensitivity and accuracy in roll-over detection difficult to obtain. Specifically, known systems tend to use sensors having thresholds which are tripped very late in the roll-over to provide a high degree of accuracy in the roll-over detection. However, waiting until very late in the roll-over to confirm a detection significantly degrades roll-over sensitivity. Reduced sensitivity correspondingly reduces the period of time in which appropriate vehicle safety devices can be actuated in response to a roll-over detection. The mechanical action is also subject to performance degradation over time.
Furthermore, some roll-over arrangements have attempted to increase reliability by utilizing a plurality of sensors positioned in different locations on the vehicle. However, each individual sensor tends to suffer from the sensitivity/reliability problem described above, while the overall system significantly increases the cost and physical space requirements for vehicle roll-over detection.